Comparative study of starches in milk cream : rheological analysis and microstructural characterization of pore network after freeze-drying

Abstract

This dissertation investigates the rheological properties and microstructural characteristics of milk cream modified with different types of starches—potato, corn, and rice—subjected to varying temperatures. It focuses on starch utilization in food technology, particularly in dairy-based products, under the context of optimizing texture and stability through freeze-drying. Methodologically, the study employed systematic sample preparations, rheological measurements, and detailed microstructural analysis using microscopy techniques, ImageJ software, and Microsoft Excel for data analysis. Key findings indicate that temperature significantly impacts viscosity and microstructure, while each starch type responded uniquely to freeze-drying processes, which affects the textural quality and stability of the final products. While all three starches showed increased viscosity with temperature, rice starch displayed a critical swelling temperature at 85°C, beyond which viscosity changes were minimal. Microstructural analysis revealed that increased temperature led to diminished integrity of pore structures across all starch types, despite varying pore size distributions. The study concludes that understanding these properties can greatly aid in refining food processing applications and enhancing product quality and efficiency. The dissertation notes the limitations in directly correlating rheological data with microstructural changes due to varying experimental conditions. Future research could explore the impact of pore and network distributions on mechanical or textural attributes like hardness or cohesiveness, potentially offering deeper insights into the formulation strategies for starch-based food products.